Flyover noise measurements were conducted on an aircraft ARJ21 aiming at landing gear noise prediction schemes. The analysis is based on acoustic dedopplerized spectra and localization maps was calculated with the pressure signals of a acoustic phased array with 30 microphones. The acoustic phased array is a spatially distributed set of microphones which simultaneously sample the acoustic field. The doppler shifts was removed using linear interpolation.By appropriately time delaying the output of individual microphones, the origin and level of noise source(the landing gear) can potentially be determined. The success of this approach depends largely on the phased array design, and the array data processing method. This paper focuses on the two areas.
The Effect of Flow Circulation on the Scattering of Landing Gear Noise